The aging process in aluminum alloy 2024 studied by means of eddy currents

In situ structural characterization of ageing kinetics in aluminum alloy 2024 across angstrom-to-micrometer length scales

“…To achieve this, ex situ methods such as transmission electron microcopy (TEM) [4, 9], three dimensional atom probe [10, 11], and X-ray diffraction [12] have been used to examine the precipitate structure and morphology. Indirect methods such as hardness testing [13], specific resistivity [14], electrical conductivity [15], and differential scanning calorimetry [16] have also been used to provide information associated with the changes in the quantity of the precipitates. From a structure-characterization point of view, an in situ direct investigation of the entire precipitation process over all the relevant length scales, which acts to reveal the morphology and kinetic growth mode of the precipitation phases, remains elusive.…”

effects of heat treatment on the microstructure and mechanical properties of the AA2618 DC cast plate /

“…Rosen and Horowitz [47] found that there is an initial decrease in conductivity at Tariq et al [51] observed that electrical conductivity measurement results of AA2014, AA2024 and AA2219 aluminum alloys exhibited a linear trend, that is, conductivity increased with aging time up to peak hardness condition. Further aging above peak hardness resulted in decrease in conductivity which proved the over-aging of the structure.…”

“…As can be observed, the hardness of surface samples increases rapidly from 76. The decrease in the electrical conductivity of the AA2618 alloy, during the first few hours of the artificial aging at 175 °C and after the natural aging, is possibly due to the formation of GPB zones [47]. The effective scattering of electrons by the evenly dispersed GPB zones leads to increase in the electrical resistance, that is, decrease in the electrical conductivity.…”

“…The variation in the electrical conductivity with aging is complex and results from a number of contributions [46] including changes in the scattering of conduction electrons from (1) the vacancies quenched in during the rapid cooling after solution heat treatment, (2) the alloying atoms present in the matrix, (3) the Guinier-Preston (GP) zones with dimensions comparable with the electron wavelength and (4) the boundaries of the zones or clusters [47]. Under the combination effect of these two competing processes, the electrical conductivities of natural aged samples yield a decreasing tendency with increasing aging time [47].…”

Evaluation of precipitation reaction in 2024 Al–Cu alloy through ultrasonic parameters

“…Measurements as a function of ageing time at various temperatures were found to exhibit prominent changes and anomalies related to the formation of precipitates. The influence of precipitation kinetics during ageing on hardness in both unstretched and plastically deformed 2024 alloy specimens was investigated by Rosen et al [19]. Rosen et al [20] characterized sound velocity and attenuation, eddy current and hardness measurements on precipitation-hardened 2024 alloy subjected to a series of different pre-ageing heat treatments prior to various tempers.…”